A line type resonator of a TEM (Transverse Electromagnetic mode) mode formed on a substrate is commonly used in a high-frequency oscillator for generating a signal with a high frequency of a microwave band or more. Also, a multiplying oscillation configuration known as a push-push oscillator in which the line type resonator of the TEM mode is combined with two negative resistance circuits is used in the high-frequency oscillator. This oscillator includes an oscillator as shown in, for example, Patent Reference 1. A circuit configuration of a conventional push-push oscillator is disclosed in this Reference.
FIG. 9 shows a circuit configuration of a conventional push-push oscillator disclosed in Patent Reference 1. The push-push oscillator shown in FIG. 9 is constructed of a resonator unit 3 and an oscillator unit 4 including two same and symmetrical oscillation units made of a Colpitts oscillator etc. It is constructed so that two outputs from the oscillator unit 4 are mutually inverted 180° in phase and by a synthetic circuit 5 having a transmission line with the same electrical length, fundamental and odd harmonic components are canceled in the output end and only even harmonic components can be doubled and outputted.
Also, in Patent Reference 1, a configuration of being synthesized in opposite phase in a synthetic circuit is shown and a configuration of achieving noise reduction by canceling a noise component inputted from the outside to two oscillation units in phase in the output end is also shown.
Also, there is a multiplying oscillator shown in Patent Reference 2 as a second conventional art. FIG. 10 shows a configuration of a triple-push type oscillator constructed of three oscillation transistors disclosed in Patent Reference 2. In this configuration, a circuit by the three oscillation transistors is constructed so that oscillation signals oscillate mutually in a phase difference of 120° and each output is synthesized by an in-phase synthetic circuit and thereby, threefold harmonics of fundamental waves are multiplied and outputted.
In the conventional multiplying oscillator (Patent Reference 1) described above, outputs oscillated by two oscillators to have a phase difference of 180° are synthesized in phase and thereby, an oscillation signal two times a fundamental frequency can be obtained. Also, in the multiplying oscillator described in Patent Reference 2, outputs oscillated by three oscillators to have a phase difference of 120° are synthesized in phase and thereby, an oscillation signal three times a fundamental frequency can be obtained.    Patent Reference 1: JP-A-4-175001    Patent Reference 2: JP-A-2006-135563